The invention relates to an operating mechanism of an electrical circuit breaker having a pair of separable contacts, housed in a moulded insulating case, and comprising:
a manual operating handle pivotally mounted on a spindle between an open position O and a closed position F, PA1 a transmission rod coupled to the handle to form a toggle-joint, PA1 a return spring of the handle to the open position O, PA1 a plate mounted with rotation on a pivot, and having a latching stop cooperating by latching with the free end of the rod, so as to form a mechanical link between the handle and the plate, PA1 a trip lever to cause said mechanical link to be interrupted by unlatching the rod and the stop, following a fault bringing about automatic tripping of the mechanism, independently from the handle, and PA1 an elastic system ensuring contact pressure in the closed position of the contacts and movement of the plate to the open position after tripping has occurred.
A mechanism of the kind mentioned authorizes manual control by pivoting the operating handle and automatic control by tripping controlled by means of a thermal and/or electromagnetic trip release causing the kinematic chain between the handle and the contact arm to be interrupted in the event of an overload occurring. The mechanical parts actuating the mechanism are mounted on joints generally formed by needles individually housed in bearings arranged either in the insulating case or in a pair of fixed support plates. Assembly of such a mechanism is complicated and requires accurate positioning of the actuating parts which makes the circuit breaker assembly time longer. The unlatching force exerted by the trip lever to break the mechanical link is relatively high and increases the tripping time.
The object of the present invention is to achieve an operating mechanism of simple and reliable construction, suited both to assembly automation and to reducing the tripping time of a miniature circuit breaker.